1. Technical Field
The present invention relates to an image reading apparatus which reads an image of a document and a recording apparatus including the image reading apparatus.
2. Related Art
In a recording apparatus which performs recording on a recording medium, there is an apparatus which is integrally configured of a recording mechanism portion which performs the recording on the recording medium, and a reading mechanism portion (also referred to as an image reading apparatus and a scanner) which reads a document.
However, in a moving mechanism of a reading unit in a flat-bed type image reading apparatus, there is a method of fixing the reading unit to a timing belt hooked to a driving pulley which rotates by a driving source and a driven pulley which is rotated to be driven by the driving pulley, and of attracting the reading unit by rotating the driving pulley and by moving the timing belt.
For example, in JP-A-11-215320, the timing belt stretches to the driving pulley and the driven pulley which are provided at both ends in the moving direction of the reading unit.
Here, the timing belt is configured so that a predetermined tensile force (tension) is applied by a belt tension mechanism.
In JP-A-11-215320, the driven pulley is pivotally supported to be rotatable around a holder that is movable in the winding direction of an endless belt, the holder is biased in the direction of being separated from the driving pulley by a biasing unit, such as a spring, and the tension is applied to the timing belt.
In this configuration, in the moving direction of the reading unit, an operation range of the driven pulley biased by the biasing unit becomes necessary in addition to a moving region of the reading unit, and there is a limit to reduction of the size of the image reading apparatus.